1. Field of the Invention
The present invention relates to an image forming apparatus. More particularly, the present invention relates to an image forming apparatus having an agitator that prevents a collection path from being clogged by toner.
2. Description of the Related Art
In general, an image forming apparatus forms a desired image by receiving a digital image signal, forming an electrostatic latent image on a photosensitive medium using an exposing apparatus such as a laser scanning unit, developing the electrostatic latent image into a toner image using toner, transferring the toner image to a print medium, and fusing the toner image on the print medium by applying heat and pressure.
Image forming apparatuses can be generally classified as either dry type or wet type depending on the type of toner and carrier used. Dry type image forming apparatuses can be further classified as either mono-component systems or dual-component systems. A mono-component system forms an image by supplying toner alone. A dual-component system forms an image by supplying a carrier on which toner particles adhere.
In a mono-component system, after the toner image on the photosensitive medium is transferred to the print medium, any excess toner remaining on the surface of the photosensitive medium is removed by a cleaning blade and collected by a collection apparatus for reuse. In a dual-component system, the carrier is not supplied to the photosensitive medium. Instead, the carrier is collected while the toner particles are supplied to the photosensitive medium to develop a toner image. Thus, like in a mono-component system, any excess toner particles remaining on the surface of the photosensitive medium are removed by a cleaning blade and collected by a collection apparatus for reuse. It should be noted that these descriptions relate to forming a black and white image. When a color image is formed, it is difficult to reuse any collected toner because the various color toners are mixed together in the toner image remaining on the surface of the photosensitive medium.
Toner is a light powder, and during the process of collecting the toner removed by the cleaning blade, the toner transfer path can become clogged by hardened toner. When the toner transfer path is clogged, the collected toner is not supplied to a developing chamber. Instead, it leaks out of the developing apparatus, or it increases the rotational torque of a toner transfer apparatus, causing damage to the toner transfer apparatus.
Thus, due to the toner clogging, the developer needs to be replaced, even though the remainder of the developer still has a useful life span. This increases costs. To prevent the necessity of replacing the entire developer, a separate transfer apparatus to transfer toner along the toner transfer path is provided. The separate transfer apparatus smoothly collects toner without accumulating toner on the toner transfer path. Since the transfer apparatus needs to be installed separately, however, the cost of the system increases.
Accordingly, there is a need for an image forming apparatus with an improved system for collecting and reusing toner.